As phallotoxins are not taken up by intestinal epithelial cells, they do not play a role in poisoning by the death cap mushroom. The toxic effects after eating the mushroom are caused solely by amatoxins 1,2. However, like amatoxins, phallotoxins have become important tools in biochemical and biological research. They inhibit the conversion of actin F into actin G and disturb the dynamic equilibrium of these forms which are necessary in cell functions 3. In addition, when taken up selectively by hepatocytes, they cause cholestasis by interaction with the polymerization of hepatocellular actin and are used as hepatotoxic substances 4,5. Phalloidin was the first phallotoxin isolated from Amanita phalloides. Other toxins derived from this structure were then characterized. Phallotoxins are dicyclic heptapeptides which are divided into two groups. The first group consists of neutral molecules: phalloin (PHN), phalloidin (PHD), phallisin (PHS) and prophalloin (PPN). The second consists of the acid molecules phallacin (PCN), phallacidin (PCD) and phallisacin (PSC). The presence of an hydroxyl group on proline makes these molecules toxic. The LD50 of PPN, for example, which has lost this OH, is ten times as great 6. Knowledge of the locations of phallotoxins in the mushroom was hindered by the lack of sufficiently sensitive and reliable methods of detection. The isolation techniques proposed use thin-layer or column chromatography. After separation of the toxins, identification was carried out using UV absorption spectophotometry or colorimetric reactions 7-9. High-performance liquid chromatography (HPLC) was applied mainly to biological liquids 10. Assaying was carried out using chemical or biological methods. The first methods include the evaluation of gammalactones derived from amino acids resulting from the hydrolysis of toxins and separated by column chromatography 1 and fluorimetric detection of cyclopeptides before and after hydrolysis 11. Biological techniques make use of the affinity of phallotoxins for muscle actin which is a target protein. One biological assay uses the polymerizing effect of [3H]dimethylphalloin on rabbit muscle actin 12. Another more sensitive assay is based on the protective effect of PHD on the inhibition of a pancreatic desoxyribonuclease by actin 13. Biological assaying is of great value since its high sensitivity (detection limit 6.3 ng) has made it possible to detect phallotoxins in other species of the genus Amanita such as A. vera, A. suballiacea, A. mutabilis and A. rubescens 13. However, these biological techniques result in an overall assay of these molecules and are thus ineffective in a search for the locations of the various neutral and acid phallotoxins in the mushroom. A sensitive, reproducible assaying technique is therefore proposed for the main phallotoxins present in A. phalloides. It was used to determine these toxins in each part of the mushroom (cap, stipe and volva).